High temperature tensile fracture characteristics of FGH96/IN718 inertial friction welded joint

In order to achieve highly reliable connection of FGH96 and IN718 dissimilar high-temperature alloys for aerospace applications, to provide basic data and theoretical support for the safety evaluation and life prediction of aero-engines key components. Scanning electron microscopy and metallurgical microscopy were used to study the FGH96 and IN718 dissimilar high-temperature alloy inertia friction welding joint microstructure morphology and high-temperature tensile specimens fracture morphology and fracture location. Test results show that the weld zone FGH96 and IN718 were equiaxed grain organization, the grain size is about 2 μm, the weld zone γ′ and δ strengthening phase were completely dissolved, the heat-force affected zone FGH96 side of the grain γ′also was completely dissolved, the IN718 side δ strengthening phase occured partially dissolved, the short rod-like shape was disappeared, coarse and fine crystal organization coexisted. The welded joint 650 ℃ high temperature tensile specimens were fractured with the weld zone, but the average tensile strength up to 1 080.8 MPa, basically with IN718 parent material equal strength, the high-temperature tensile specimens crack location were in the edge of the sample weld zone, the crack from the weld zone was mainly due to γ′ and δ strengthening phase basically all dissolved, the strengthening effect disappeared, the performance was reduced. The crack was generated along the grain boundary from the weld fusion line to the specimen internal expansion, the crack from the specimen edge weld area around the same time to the specimen internal expansion, under the action of axial tension to form a "platform + crater" fracture characteristics, when the crack from the specimen edge weld area local location to the specimen internal expansion, under the action of axial tension to form "platform + shear" fracture characteristics.